robot

Abstract

A robot having excellent vibration damping is provided. The robot is characterized by comprising: a base; a first arm connected to the base and rotating around a first axis; a second arm connected to the first arm and rotating around a second axis parallel to the first axis; a first shaft body connected to the second arm and rotating around a third axis parallel to the second axis; a first support portion provided to the second arm and rotatably supporting the first shaft body; and a second support portion connected to the second arm and rotatably supporting the first shaft body at a position different from the first support portion in the axial direction of the third axis.

Description

Technical Field

[0001] This invention relates to robots. Background Technology

[0002] In recent years, due to rising labor costs and a shortage of skilled workers in factories, the automation of manually performed tasks is accelerating through the use of various robots or their peripheral devices. One example of such robots is the SCARA robot described in Patent Document 1.

[0003] The SCARA robot described in Patent Document 1 has a base, a first arm connected to the base, a second arm connected to the first arm, a working axis connected to the second arm and capable of lifting, lowering and rotating, and a working axis lifting mechanism for raising and lowering the working axis.

[0004] In addition, the working shaft lifting mechanism includes: a lifting belt that transmits the driving force of the working shaft lifting motor via a drive pulley and a driven pulley; a vertical moving bracket that holds the working shaft in a rotatable manner while fixed to the lifting belt, and moves up and down together with the working shaft as the lifting belt conveys it; and a guide shaft that guides the vertical moving bracket to move up and down.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-285282

[0006] In such robots, especially during operation, the working axis may sometimes vibrate. In this case, the accuracy of the robot's operation may be reduced. Summary of the Invention

[0007] The present invention was made to address at least a portion of the aforementioned issues and can be achieved in the following manner.

[0008] The robot of the present invention is characterized by comprising: a base; a first arm connected to the base and rotating about a first axis; a second arm connected to the first arm and rotating about a second axis parallel to the first axis; a first shaft connected to the second arm and rotating about a third axis parallel to the second axis; a first support portion disposed on the second arm and rotatably supporting the first shaft; and a second support portion connected to the second arm and rotatably supporting the first shaft at a position different from the first support portion in the axial direction of the third axis. Attached Figure Description

[0009] Figure 1 This is a side view showing a first embodiment of the robot of the present invention.

[0010] Figure 2 It means Figure 1 The diagram shows a block diagram of the robot system.

[0011] Figure 3 It means Figure 1 A partial cross-sectional view of the interior of the second arm of the robotic arm shown.

[0012] Figure 4 It means Figure 3 The robotic arm shown is a cross-sectional view along line AA.

[0013] Figure 5 This is a partial cross-sectional view schematically showing the interior of the second arm of the robot according to a second embodiment of the present invention.

[0014] Figure 6 This is a partial cross-sectional view schematically showing the interior of the second arm of the robot according to the third embodiment of the present invention.

[0015] Explanation of reference numerals in the attached figures

[0016] 1…Control device, 2…Robot, 4…Rotary support, 5…Rotary support, 7…End effector, 11…Robot control unit, 12…Motor control unit, 13…Display control unit, 14…Storage unit, 15…Receiver unit, 20…Robotic arm, 21…Base, 22…First arm, 23…Second arm, 24…Third arm, 25…Drive unit, 26…Drive unit, 27…u drive unit, 28…z drive unit 41…Support section, 42…Connecting section, 42A…First part, 42B…Second part, 70…End effector mounting section, 72…Motor, 100…Robot system, 200…Cable, 230…Housing, 230C…Recess, 231…Base section, 231A…Bottom, 231B…Side wall section, 232…Cover, 241…Front end shaft, 242…Rotary support section, 243…Ball screw nut, 243A… Inner ring, 243B…Outer ring, 244…Spline nut, 244A…Inner ring, 244B…Outer ring, 245…Outer cylinder, 246…Rotating body, 251…Motor, 252…Reducer, 253…Position sensor, 261…Motor, 262…Reducer, 263…Position sensor, 271…Motor, 273…Position sensor, 274…Belt, 275…Pulley, 281…Motor, 283…Position sensor , 284…belt, 285…pulley, 291…front end shaft, 292…rotary support component, 293…spline nut, 293A…inner ring, 293B…outer ring, 294…outer cylinder, 295…rotating body, 301…transmission shaft, 302…rotary support part, 303…ball screw nut, 304…pulley, 310…connecting component, O1…first shaft, O2…second shaft, O3…third shaft, O4…fourth shaft. Detailed Implementation

[0017] The robot of the present invention will now be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0018] First Implementation Method

[0019] Figure 1 This is a side view showing a first embodiment of the robot of the present invention. Figure 2 yes Figure 1 The diagram shows a block diagram of the robot system. Figure 3 It means Figure 1 A partial cross-sectional view of the interior of the second arm of the robotic arm shown. Figure 4 yes Figure 3 The robotic arm shown is a cross-sectional view along line AA.

[0020] In addition, Figure 1 , Figure 3 as well as Figure 4 For ease of explanation, the x-axis, y-axis, and z-axis are shown as three mutually orthogonal axes. Furthermore, the direction parallel to the x-axis will be referred to as the "x-axis direction," the direction parallel to the y-axis as the "y-axis direction," and the direction parallel to the z-axis as the "z-axis direction." Additionally, the front end of each arrow in the illustration will be referred to as "+" (positive), and the base end as "-" (negative). The direction parallel to the +x-axis direction will be referred to as the "+x-axis direction," the direction parallel to the -x-axis direction as the "-x-axis direction," the direction parallel to the +y-axis direction as the "+y-axis direction," the direction parallel to the -y-axis direction as the "-y-axis direction," the direction parallel to the +z-axis direction as the "+z-axis direction," and the direction parallel to the -z-axis direction as the "-z-axis direction." Furthermore, the direction around the z-axis and the direction around an axis parallel to the z-axis will also be referred to as the "u-axis direction."

[0021] In addition, for ease of explanation, the following will be... Figure 1 , Figure 3 as well as Figure 4 The +z axis direction, i.e., the upper side, is also called "up" or "above," and the -z axis direction, i.e., the lower side, is also called "down" or "below." Additionally, regarding the robotic arm 20, [the text continues with further details about the robotic arm 20]. Figure 1 The side of the base 21 is called the "base end," and its opposite side, namely the end effector 7 side, is called the "front end." Additionally, Figure 1 The z-axis direction, i.e., the up-down direction, is set as the "vertical direction", and the x-axis direction and y-axis direction, i.e., the left-right direction, are set as the "horizontal direction".

[0022] Figure 1 and Figure 2The robot system 100 shown is, for example, a device used in operations such as holding, conveying, assembling, and inspecting workpieces such as electronic components and electronic devices. The robot system 100 includes a control device 1, a robot 2, and an end effector 7.

[0023] Furthermore, the control device 1 is located at a different position from the robot 2, namely, outside the robot 2. In the illustrated structure, the robot 2 and the control device 1 are electrically connected by a cable 200 (hereinafter simply referred to as "connection"), but this is not a limitation; the cable 200 can also be omitted, and communication can be performed wirelessly. That is, the robot 2 and the control device 1 can be connected via wired communication, or they can be connected via wireless communication.

[0024] In the structure shown in the diagram, robot 2 is a horizontal multi-joint robot, namely, a SCARA robot.

[0025] like Figures 1-3 As shown, robot 2 has a base 21, a first arm 22, a second arm 23, and a third arm 24 that serves as the working head. The first arm 22, the second arm 23, and the third arm 24 constitute the robotic arm 20.

[0026] Additionally, the robot 2 includes: a drive unit 25 for rotating the first arm 22 relative to the base 21; a drive unit 26 for rotating the second arm 23 relative to the first arm 22; a u drive unit 27 for rotating the front end shaft (first shaft) 241 of the third arm 24 relative to the second arm 23; and a z drive unit 28 for moving the front end shaft 241 relative to the second arm 23 along the z-axis.

[0027] like Figure 1 as well as Figure 2 As shown, the drive unit 25 is built into the base 21 and has a motor 251 that generates driving force, a reducer 252 that reduces the driving force of the motor 251, and a position sensor 253 that detects the rotation angle of the rotating shaft of the motor 251 or the reducer 252.

[0028] The drive unit 26 is built into the housing 230 of the second arm 23 and includes a motor 261 that generates driving force, a reducer 262 that reduces the driving force of the motor 261, and a position sensor 263 that detects the rotation angle of the rotating shaft of the motor 261 or the reducer 262.

[0029] The drive unit 27 is built into the housing 230 of the second arm 23, and has a motor 271 that generates driving force and a position sensor 273 that detects the rotation angle of the rotating shaft of the motor 271.

[0030] The z-drive unit 28 is built into the housing 230 of the second arm 23, and has a motor 281 that generates driving force and a position sensor 283 that detects the rotation angle of the rotating shaft of the motor 281.

[0031] For example, AC servo motors, DC servo motors, and other servo motors can be used as motors 251, 261, 271, and 281.

[0032] Furthermore, the speed reducers 252 and 262 can be, for example, planetary gear type speed reducers, wave gear devices, etc. Additionally, the position sensors 253, 263, 273, and 283 can be, for example, angle sensors.

[0033] Drive unit 25, drive unit 26, u drive unit 27 and z drive unit 28 are respectively connected to corresponding motor drivers (not shown) and are controlled by robot control unit 11 of control device 1 via motor drivers.

[0034] The base 21 is fixed to a floor surface (not shown), for example, by bolts. A first arm 22 is connected to the upper end of the base 21. The first arm 22 is rotatable relative to the base 21 about a first axis O1 along the vertical direction. When the drive unit 25, which rotates the first arm 22, is driven, the first arm 22 rotates in the horizontal plane relative to the base 21 about the first axis O1. Furthermore, the amount of rotation of the first arm 22 relative to the base 21 can be detected by a position sensor 253.

[0035] Furthermore, a second arm 23 is connected to the front end of the first arm 22. The second arm 23 is rotatable relative to the first arm 22 about a second axis O2 along the vertical direction. The axial direction of the first axis O1 is the same as the axial direction of the second axis O2. That is, the second axis O2 is parallel to the first axis O1. When the drive unit 26, which drives the second arm 23 to rotate, is driven, the second arm 23 rotates relative to the first arm 22 about the second axis O2 in the horizontal plane. In addition, the drive of the second arm 23 relative to the first arm 22 can be detected by the position sensor 263, specifically, the amount of rotation can be detected. That is, the second axis O2 is the center of the output rotation axis of the reducer 262.

[0036] like Figure 3 As shown, the second arm 23 has a housing 230, which has a base portion 231 and a cover 232. Inside the housing 230, i.e. on the base portion 231, drive unit 26, u drive unit 27 and z drive unit 28 are arranged sequentially from the +y axis side.

[0037] like Figure 4As shown, the second arm 23 is a structure supported and protected by a cover 232 within the base portion 231. The base portion 231 is a rigid body made of metal or similar materials, which provides stable support for the internal structure and improves vibration damping. The cover 232 is made of a lightweight material such as resin.

[0038] The base portion 231 has a bottom portion 231A and a side wall portion 231B erected from the bottom portion 231A. The bottom portion 231A has a recess 230C. A portion of the recess 230C on the -z axis side is open to the -z axis side, and a rotary support portion 242 is embedded in the open portion, through which a front end shaft 241 is inserted.

[0039] The bottom 231A is plate-shaped or block-shaped with thickness in the z-axis direction. The shape of the bottom 231A when viewed from the z-axis direction is not particularly limited, for example, it can be rectangular or elliptical.

[0040] The sidewall portion 231B is provided around the entire circumference of the edge portion of the surface on the +z axis side of the bottom 231A. However, it is not limited to this structure; the sidewall portion 231B may be provided only on the edges on the +x axis side and the -x axis side.

[0041] A third arm 24 is provided at the front end of the second arm 23. The third arm 24 has a front end shaft 241 and a rotatable support portion 242 that rotatably supports the front end shaft 241.

[0042] The front end shaft 241 is rotatable relative to the second arm 23 about a third axis O3 along the vertical direction, and is also movable (lifting) in the vertical direction. The front end shaft 241 is the foremost arm of the robotic arm 20.

[0043] Additionally, a ball screw nut 243 and a spline nut 244 are provided midway along the length of the front shaft 241, and the front shaft 241 is supported by them. These ball screw nuts 243 and spline nuts 244 are arranged separately from the +z axis side.

[0044] The ball screw nut 243 has an inner ring 243A and an outer ring 243B concentrically disposed on the outer periphery of the inner ring 243A. A plurality of balls (not shown) are disposed between the inner ring 243A and the outer ring 243B, and the inner ring 243A and the outer ring 243B rotate relative to each other as the balls move.

[0045] Furthermore, the inner ring 243A has a portion protruding from the outer ring 243B, and a belt 284, described later, is wound around this protruding portion. Additionally, a front end shaft 241 is inserted into the inner ring 243A, and as described later, the front end shaft 241 is supported in a manner that allows it to move along the z-axis. The outer ring 243B is fixed to the base portion 231.

[0046] The spline nut 244 has an inner ring 244A and an outer ring 244B concentrically disposed on the outer periphery of the inner ring 244A. A plurality of balls (not shown) are disposed between the inner ring 244A and the outer ring 244B, and the inner ring 244A and the outer ring 244B rotate relative to each other as the balls move.

[0047] Furthermore, the inner ring 244A has a portion protruding from the outer ring 244B, and the belt 274 (described later) is wound around this protruding portion. Additionally, a front end shaft 241 is inserted into the inner ring 244A, supporting the front end shaft 241 in a manner rotatable about the z-axis, i.e., in the u-axis direction. Furthermore, the outer ring 244B is fixed to the recess 230C of the base portion 231 (described later).

[0048] Additionally, a swivel support 242 is provided on the -z axis side of the spline nut 244. This swivel support 242 is a first support having an outer cylinder 245 and a rotating body 246 disposed inside the outer cylinder 245. The outer cylinder 245 is fixed to a base portion 231 within the housing 230 of the second arm 23. On the other hand, the rotating body 246 is fixed to the front end shaft 241, but can be rotatably supported on the outer cylinder 245 together with the front end shaft 241 around the z-axis, i.e., in the u-axis direction.

[0049] When the u-drive unit 27, which drives the front shaft 241 to rotate, is driven, the front shaft 241 rotates in both directions around the z-axis, i.e., it rotates. In addition, the amount of rotation of the front shaft 241 relative to the second arm 23 can be detected by the position sensor 273.

[0050] Furthermore, when the z-drive unit 28, which drives the front shaft 241 to move along the z-axis, is driven, the front shaft 241 moves in the vertical direction, i.e., along the z-axis. Additionally, the amount of movement of the front shaft 241 relative to the second arm 23 in the z-axis direction can be detected by the position sensor 283.

[0051] Furthermore, various end effectors are detachably connected to the front end of the front shaft 241. There are no particular limitations on the end effector; examples include end effectors for holding conveyed objects, end effectors for processing objects, and end effectors for inspection. In this embodiment, the end effector 7 is detachably connected.

[0052] Furthermore, in this embodiment, the end effector 7 is not a component of the robot 2, but some or all of the end effector 7 may be a component of the robot 2. Additionally, in this embodiment, the end effector 7 is not a component of the robotic arm 20, but some or all of the end effector 7 may be a component of the robotic arm 20.

[0053] In addition, in this embodiment, the end effector 7 can be attached to and detached from the robotic arm 20, but it is not limited to this. For example, the end effector 7 may not be able to detach from the robotic arm 20.

[0054] like Figure 2 As shown, the control device 1 includes a robot control unit 11, a motor control unit 12 (end-effector control unit), a display control unit 13, a storage unit 14, and a receiving unit 15, which respectively control the drive of each part of the robot system 100, such as the robot 2 and the motor 72 of the end-effector 7.

[0055] Furthermore, the control device 1 is configured such that communication is possible between the robot control unit 11, the motor control unit 12, the display control unit 13, the storage unit 14, and the receiving unit 15. That is, the robot control unit 11, the motor control unit 12, the display control unit 13, the storage unit 14, and the receiving unit 15 are interconnected via wired or wireless communication.

[0056] In addition, robot 2 and end effector 7 are connected to control device 1 via wired or wireless communication, respectively.

[0057] The robot control unit 11 controls the drive of the robot 2, i.e., the drive of the robotic arm 20, etc. The robot control unit 11 is a computer with programs such as an operating system installed. This robot control unit 11, for example, has a CPU as a processor, RAM, and ROM storing programs. Furthermore, the functions of the robot control unit 11 can be implemented, for example, by executing various programs using the CPU.

[0058] The motor control unit 12 controls the drive of the motor 72. The motor control unit 12 is a computer with an operating system or similar programs installed. This motor control unit 12 includes, for example, a CPU as a processor, RAM, and ROM storing programs. Furthermore, the functions of the motor control unit 12 can be implemented, for example, by executing various programs using the CPU.

[0059] The display control unit 13 has the function of displaying various screens, text, etc., such as windows on a display device (not shown). The functions of this display control unit 13 can be implemented, for example, through a GPU.

[0060] Storage unit 14 has the function of storing various information (including data, programs, etc.). Storage unit 14 stores control programs, etc. The functions of storage unit 14 can be implemented through an external storage device (not shown) such as ROM.

[0061] The receiving unit 15 has the function of accepting input from an input device (not shown). The function of the receiving unit 15 can be implemented, for example, through an interface circuit.

[0062] Next, the interior of the second arm 23 will be described.

[0063] In Robot 2, such as Figure 3 As shown, the housing 230 of the second arm 23 is provided with a u-drive unit 27 for rotating the third arm 24 about the z-axis, a z-drive unit 28 for moving the third arm 24 along the z-axis, a belt 274 and a belt 284.

[0064] like Figure 3 As shown, in addition to the motor 271 and position sensor 273 mentioned above, the u-drive unit 27 also has a pulley 275. They are arranged in the order of position sensor 273, motor 271, and pulley 275, starting from the +z axis side, and are fixed to the bottom of the recess 230C. The pulley 275 is fixed to the rotation shaft of the motor 271, and the rotational force of the motor 271 is transmitted to the pulley 275.

[0065] Additionally, pulley 275 is connected to the inner ring 244A of spline nut 244 located on the front end shaft 241 via belt 274. Belt 274 is an annular belt wound around pulley 275 and inner ring 244A, and has teeth (not shown) on its inner side, i.e., on the sides of pulley 275 and inner ring 244A. The teeth of belt 274 mesh with the exposed teeth (not shown) of pulley 275 and inner ring 244A, respectively.

[0066] In this u-drive unit 27, the rotational force of the motor 271 is transmitted to the belt 274 via the pulley 275, causing the belt 274 to rotate. Through the rotation of the belt 274, its rotational force is transmitted to the front shaft 241 via the spline nut 244. This rotational force is transmitted to the front shaft 241 via the inner circumference of the inner ring 244A and a spline groove (not shown) of the front shaft 241, enabling the front shaft 241 to move along the u-axis direction, i.e., to rotate.

[0067] like Figure 3 As shown, in addition to the motor 281 and position sensor 283 mentioned above, the z-drive unit 28 also has a pulley 285. They are arranged from the +z axis side in the order of position sensor 283, motor 281, and pulley 285. The pulley 285 is fixed to the rotation shaft of the motor 281, and the rotational force of the motor 281 is transmitted to the pulley 285.

[0068] Additionally, pulley 285 is connected via belt 284 to the exposed portion of the inner ring 243A of ball screw nut 243 located on the front end shaft 241. Belt 284 is an annular belt wound around pulley 285 and inner ring 243A, and has teeth (not shown) on its inner side, i.e., on the sides of pulley 285 and inner ring 243A. The teeth of belt 284 mesh with the teeth (not shown) of pulley 285 and inner ring 243A, respectively.

[0069] In this z-drive unit 28, the rotational force of the motor 281 is transmitted to the belt 284 via the pulley 285, causing the belt 284 to rotate. Through the rotation of the belt 284, its rotational force is transmitted to the front shaft 241 via the inner ring 243A of the ball screw nut 243. This rotational force is redirected by the inner circumference of the inner ring 243A and the ball screw groove of the front shaft 241, enabling the front shaft 241 to move along the z-axis, i.e., to move up and down.

[0070] Furthermore, in this embodiment, the u-drive unit 27 is a unit in which the motor 271 and the position sensor 273 are coaxially fixed. However, in this invention, it is not limited to this, and the motor 271 and the position sensor 273 may also be configured at different positions.

[0071] Similarly, in this embodiment, the z-drive unit 28 is a unit in which the motor 281 and the position sensor 283 are coaxially fixed. However, in this invention, it is not limited to this, and the motor 281 and the position sensor 283 may also be configured at different positions.

[0072] The overall structure of robot 2 has been described above. In such robot 2, to improve the accuracy of operations, it is necessary to reduce vibration during operation. In particular, the front shaft 241 experiences shaft jitter relative to the third axis O3, or vibration occurs during lifting, which can easily lead to a decrease in the overall vibration damping performance of the robotic arm 20. Therefore, in this invention, vibration damping performance is improved by adopting the following structure, which will be explained below.

[0073] like Figure 4 As shown, robot 2 includes a swivel support 4 as a second support. The swivel support 4 is a component that rotatably supports the front end shaft 241 at a position different from the swivel support 242 along the axial direction of the third axis O3; in this embodiment, it is a component that rotatably supports the front end shaft 241 at an upwardly separated position. Furthermore, in Figure 4 In the original text, ball screw nut 243, spline nut 244, belt 274, and belt 284 are omitted.

[0074] The rotating support 4 has a support 41 that supports the front end shaft 241 and a connecting part 42 that connects the support 41 to the base 231.

[0075] As a support part 41, for example, a ring-shaped component such as a bearing can be used. The support part 41 rotatably supports the front end shaft 241 and is movable along the third axis O3.

[0076] like Figure 4As shown, in this embodiment, the connecting portion 42 connects the sidewall portion 231B of the base portion 231 to the support portion 41. In this embodiment, the connecting portion 42 has a first portion 42A connected to the support portion 41 from the +x axis side and a second portion 42B connected to the support portion 41 from the -x axis side. That is, in this embodiment, the connecting portion 42 has two arms. The first portion 42A and the second portion 42B each have a portion extending from the sidewall portion 231B along the z-axis direction and a portion extending along the x-axis direction, respectively.

[0077] Furthermore, not limited to this structure, the connecting portion 42 may also be composed of a plate-like component that connects the support portion 41 to the side wall portion 231B. In this case, the connecting portion 42 may be connected around the entire circumference of the support portion 41, or it may be a structure with a partially missing arc shape.

[0078] With this structure, the front shaft 241 can be supported at different positions along its length using the rotary support 242 as the first support and the rotary support 4 as the second support. That is, the front shaft 241 is supported at two different locations along the axial direction of the third axis O3. Therefore, compared to a structure that supports the front shaft 241 at only one location, it is possible to effectively prevent or suppress shaft jitter in the front shaft 241 when driving the robotic arm 20 or when the front shaft 241 is raised or lowered. As a result, the accuracy of the work performed by the robot 2 can be improved. Furthermore, the generation of shaft jitter in the front shaft 241 caused by the driving of the second arm can also be reduced.

[0079] Thus, robot 2 comprises: a base 21; a first arm 22 connected to the base 21 and rotating about a first axis O1; a second arm 23 connected to the first arm 22 and rotating about a second axis O2 parallel to the first axis O1; a front end shaft 241, serving as a first shaft body, connected to the second arm 23 and rotating about a third axis O3 parallel to the second axis O2; a rotary support 242, serving as a first support, disposed on the second arm 23 and rotatably supporting the front end shaft 241; and a rotary support 4, serving as a second support, connected to the second arm 23 and rotatably supporting the front end shaft 241 at a different position along the axial direction of the third axis O3 than the rotary support 242. This effectively prevents or suppresses shaft jitter in the front end shaft 241 when driving the robotic arm 20 or vibration of the front end shaft 241 during lifting and lowering. As a result, the accuracy of the work performed by robot 2 can be improved.

[0080] Furthermore, the front end shaft 241, which serves as the first axis, is movable along the third axis O3. The rotary support 242, which serves as the first support, and the rotary support 4, which serves as the second support, support the front end shaft 241 in a manner that allows it to move along the third axis O3. As a result, the front end shaft 241 can move along the third axis O3, enabling it to perform operations correctly.

[0081] Furthermore, the second arm 23 has a base portion 231 and a cover 232 that covers the structure supported by the base portion 231. A rotary support portion 4, serving as a second support portion, is connected to the base portion 231. The rotary support portion 4 is fixed to the relatively rigid base portion 231, thereby further effectively preventing or suppressing shaft vibration of the front shaft 241 when driving the robotic arm 20 or vibration of the front shaft 241 during lifting and lowering. As a result, the accuracy of the work performed by the robot 2 can be improved.

[0082] Furthermore, the base portion 231 has a bottom portion 231A and a side wall portion 231B erected vertically from the bottom portion 231A, and the rotation support portion 4, which serves as the second support portion, is fixed to the side wall portion 231B. Therefore, the second portion 42B of the connecting portion 42 of the rotation support portion 4 can be provided along the vertical direction of the side wall portion 231B. Thus, the space on the bottom portion 231A can be effectively utilized, and the second arm 23 can be miniaturized.

[0083] Furthermore, in this embodiment, the support portion 41 of the rotary support portion 4 is located on the +z axis side compared to the rotary support portion 242. That is, the position where the rotary support portion 4 supports the front end shaft 241 is further away from the end effector mounting portion 70 compared to the position where the rotary support portion 242 supports the front end shaft 241. As a result, it is possible to omit the need to provide the rotary support portion 4 on the outside of the cover 232, and the rotary support portion 4 can be protected by the cover 232.

[0084] Thus, the front end shaft 241, which serves as the first shaft, has an end effector mounting portion 70 for mounting the end effector 7. In the axial direction of the third shaft O3, the distance between the position of the rotating support portion 4, which serves as the second support portion, supporting the front end shaft 241, and the end effector mounting portion 70 is longer than the distance between the position of the rotating support portion 242, which serves as the first support portion, supporting the front end shaft 241, and the end effector mounting portion 70. Therefore, the requirement to install the rotating support portion 4 on the outside of the cover 232 can be eliminated, and the cover 232 can be used to protect the rotating support portion 4.

[0085] Second Implementation Method

[0086] Figure 5 This is a partial cross-sectional view schematically showing the interior of the second arm of the robot according to a second embodiment of the present invention.

[0087] Hereinafter, a second embodiment of the robot of the present invention will be described with reference to the figure, and the differences from the first embodiment will be described below.

[0088] like Figure 5 As shown, in this embodiment, the rotary support 4 rotatably supports the front end shaft 241 at a position where it separates axially downward toward the third axis O3. In this embodiment, the connecting portion 42 connects the edge of the bottom 231A of the base portion 231 to the rotary support 4. That is, the first portion 42A and the second portion 42B each have a portion extending from the side wall portion 231B along the z-axis direction and a portion extending along the x-axis direction, respectively.

[0089] Thus, in this embodiment, the front end shaft 241, which serves as the first shaft, has an end effector mounting portion 70 for mounting the end effector 7. In the axial direction of the third shaft O3, the distance between the position of the front end shaft 241 supported by the rotary support portion 4, which serves as the second support portion, and the end effector mounting portion 70 is shorter than the distance between the position of the front end shaft 241 supported by the rotary support portion 242, which serves as the first support portion, and the end effector mounting portion 70. Therefore, even when a relatively heavy end effector 7 is installed, the rotary support portion 4 can support a position closer to the end effector 7. Consequently, excellent vibration damping can be achieved when a relatively heavy end effector 7 is installed.

[0090] Third Implementation Method

[0091] Figure 6 This is a partial cross-sectional view schematically showing the interior of the second arm of the robot according to the third embodiment of the present invention.

[0092] Hereinafter, a third embodiment of the robot of the present invention will be described with reference to the figure, and the differences from the first embodiment will be described below.

[0093] like Figure 6 As shown, the third arm 24 has a front end shaft 291, a rotary support member 292 that rotatably supports the front end shaft 291, a transmission shaft (second shaft) 301, a third support portion, i.e., the rotary support portion 302, that rotatably supports the transmission shaft 301, and a connecting member 310 that connects the front end shaft 291 and the transmission shaft 301. In this embodiment, the front end shaft 291 is a ball spline shaft, and the transmission shaft 301 is a ball screw shaft.

[0094] The front shaft 291 is provided with a spline nut 293. The spline nut 293 has an inner ring 293A and an outer ring 293B concentrically arranged on the outer periphery of the inner ring 293A. Between these inner rings 293A and outer rings 293B, a plurality of balls (not shown) are arranged, and the inner rings 293A and outer rings 293B rotate relative to each other as the balls move.

[0095] Additionally, the inner ring 293A has a portion that protrudes from the outer ring 293B, and a belt 274 is wound around this protruding portion. Furthermore, a front end shaft 291 is inserted into the inner ring 293A, and the front end shaft 291 is supported in a manner that allows it to rotate about the z-axis, i.e., along the u-axis.

[0096] Additionally, a swivel support member 292 is provided on the -z axis side of the spline nut 293. This swivel support member 292 has an outer cylinder 294 and a swivel body 295 disposed inside the outer cylinder 294. The outer cylinder 294 is fixed to a base portion 231 within the housing 230 of the second arm 23. On the other hand, the swivel body 295 is fixed to the front end shaft 291, but can be rotatably supported on the outer cylinder 294 together with the front end shaft 291 around the z-axis, i.e., in the u-axis direction.

[0097] When the u-drive unit 27 is driven, the front shaft 291 rotates in both directions around the z-axis, that is, it rotates. In addition, the amount of rotation of the front shaft 291 relative to the second arm 23 can be detected by the position sensor 273.

[0098] Additionally, at the end of the front shaft 291 on the +z axis side, the connecting member 310 is installed in a state that allows it to rotate relative to the front shaft 291 but prevents it from moving in the up and down directions.

[0099] A pulley 304 is provided on the -z axis side of the transmission shaft 301. A belt 284 is wound on the pulley 304. The rotational force of the motor 281 is transmitted to the transmission shaft 301 through the belt 284 and the pulley 304, thereby causing the transmission shaft 301 to rotate in both directions, i.e., to rotate.

[0100] Furthermore, the ball screw nut 303 is disposed at the end of the transmission shaft 301 on the +z axis side and is mounted to the aforementioned connecting member 310 in a non-rotatable state. Therefore, the ball screw nut 303 moves in the up-down direction as a whole with the connecting member 310 and the front shaft 291, driven by the rotation of the transmission shaft 301 under the drive of the z drive unit 28. In addition, the amount of movement of the front shaft 291 relative to the second arm 23 in the z-axis direction can be detected by the position sensor 283.

[0101] Additionally, the transmission shaft 301 is positioned on the +y axis side relative to the front shaft 291 and extends along the fourth axis O4, which is parallel to the third axis O3. The transmission shaft 301 is rotatably supported on the base portion 231 via the swivel support portion 302.

[0102] In this robot 2, in addition to the front shaft 291, the transmission shaft 301 is also supported at two other locations. That is, the robot 2 has a rotary support 302 as a third support and a rotary support 5 as a fourth support, which rotatably supports the transmission shaft 301 at a different location than the rotary support 302. The structure of the rotary support 5 is substantially the same as that of the rotary support 4, so detailed description is omitted.

[0103] Thus, robot 2 comprises: a transmission shaft 301, serving as a second axis, configured along a fourth axis O4 that is different from and parallel to the third axis O3, transmitting the driving force of motor 281 to a front end shaft 291, serving as a first axis, via a connecting member 310; a rotary support 302, serving as a third support, provided on the second arm 23, rotatably supporting the transmission shaft 301; and a rotary support 5, serving as a fourth support, connected to the second arm 23, rotatably supporting the transmission shaft 301 at a position different from the rotary support 302 along the axial direction of the fourth axis O4. Therefore, even with the structure having a front end shaft 291 and a transmission shaft 301, excessive vibration of the robotic arm 20 can be prevented or suppressed when driving the robotic arm 20. As a result, the accuracy of the work performed by robot 2 can be improved.

[0104] Furthermore, the positions of the rotary support 4 and the rotary support 5 in the z-axis direction can be the same or different. In different cases, it is preferable to position the rotary support of the longer shaft of the front shaft 291 and the transmission shaft 301 at a higher position. In this way, by appropriately positioning the support according to the length of the shaft, excessive vibration of the robotic arm 20 can be more effectively prevented or suppressed. As a result, the accuracy of the work performed by the robot 2 can be improved.

[0105] Thus, it is preferable that the rotary support 4, which serves as the second support, and the rotary support 5, which serves as the fourth support, are positioned differently along the axial direction of the third axis O3. This allows the support positions to be appropriately adjusted according to the length of the shaft. Consequently, excessive vibration of the robotic arm 20 can be more effectively prevented or suppressed. As a result, the accuracy of the operations performed by the robot 2 can be improved.

[0106] The robot of the present invention has been described above with reference to the illustrated embodiments, but the present invention is not limited thereto, and the structure of each part can be replaced with any structure having the same function. In addition, other arbitrary components may be added.

[0107] Furthermore, in the above embodiment, the number of rotation axes of the robotic arm is three, but in this invention, it is not limited to this, and the number of rotation axes of the robotic arm can be, for example, two or four or more. That is, in the above embodiment, the number of arms is three, but in this invention, it is not limited to this, and the number of arms can be, for example, two or four or more.

[0108] Furthermore, in the above embodiment, the front end shaft 241 can rotate relative to the second arm 23 about a third axis O3 along the vertical direction, and can move (lift or lower) in the vertical direction, but is not limited to this. For example, the front end shaft 241 can also move (lift or lower) only in the vertical direction. In this case, the u-drive unit 27 can be omitted in the second arm 23, and only the z-drive unit 28 is mounted.

Claims

1. A robot, characterized in that, The robot is equipped with an end effector and possesses: abutment; The first arm is connected to the base and rotates about the first axis; The second arm is connected to the first arm and rotates about a second axis parallel to the first axis; A first shaft is connected to the second arm, and the first shaft moves axially toward a third axis parallel to the second axis and rotates about the third axis; A first motor is disposed on the second arm to drive the first shaft in such a way that the first shaft moves axially toward the third shaft; A second motor is disposed on the second arm to drive the first shaft body by causing the first shaft body to rotate about the third shaft body; The connecting component is mounted on the first shaft in a state in which it can rotate relative to the first shaft but cannot move axially toward the third shaft relative to the first shaft. The second shaft is disposed on the second arm and arranged along a fourth shaft that is different from and parallel to the third shaft, and transmits the driving force of the first motor to the first shaft via the connecting member. A first support portion is disposed on the second arm and rotatably supports the first shaft body; A second support portion, connected to the second arm, rotatably supports the first shaft body at a position on the axial direction of the third shaft that differs from that of the first support portion; and An end effector mounting section is disposed on the first shaft, and the end effector is mounted thereon. The second arm has a structure, a base portion supporting the structure, and a cover covering the structure. In the first shaft, the end effector mounting portion is provided at one end relative to the first support portion, and the connecting member is provided at the other end relative to the first support portion. The first support portion is disposed on the base portion. The second support portion is disposed within the first shaft body between the first support portion and the connecting member, and is covered by the cover. The base portion has a bottom and a side wall portion that rises vertically from the bottom. The bottom has a recess, and the first support portion is embedded in the portion of the recess that opens towards the axial direction. The second support portion has a support portion that supports the first shaft and a connecting portion that connects the support portion to the base portion. The connecting portion connects the side wall portion of the base portion to the support portion.

2. The robot according to claim 1, characterized in that, The first support portion and the second support portion support the first shaft body in a manner that allows the first shaft body to move along the third axis.

3. The robot according to claim 1, characterized in that, Along the axial direction of the third shaft, the distance between the position where the second support supports the first shaft and the end effector mounting portion is longer than the distance between the position where the first support supports the first shaft and the end effector mounting portion.

4. The robot according to claim 1, characterized in that, have: A third support portion is disposed on the second arm and rotatably supports the second shaft; and The fourth support is connected to the second arm and rotatably supports the second shaft at a position different from that of the third support in the axial direction of the fourth shaft.

5. The robot according to claim 4, characterized in that, The second support and the fourth support are positioned differently along the axial direction of the third shaft.

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